<!DOCTYPE html>
<html>
	<head>
		<meta  charset="UTF-8">
		<title>45</title>
	</head>
	<!--百度统计-->
	<script>
var _hmt = _hmt || [];
(function() {
  var hm = document.createElement("script");
  hm.src = "https://hm.baidu.com/hm.js?04e828ac441acffeb4a6bc5698f79d55";
  var s = document.getElementsByTagName("script")[0]; 
  s.parentNode.insertBefore(hm, s);
})();
</script>
	<body>
		<script>
			function 数学(运算, a, b) {
				switch(运算) {
				case "乘法":
				return 乘法(a,b);
				case "除法":
				return 除法(a,b);
				}
				function 乘法(x,y){
				return x*y;
				}
				function 除法(n,d){
				return n/d;
				}
			}
			alert(数学("乘法", 5, 4));
		</script>
	</body>
</html>
